Over the centuries, the sweet spot has been identified: something you hold in your hand, something you can curl up with in bed. Devices like the Kindle, with its 167 dot-per-inch E Ink display, with type set in a serif font called Caecilia, can subsume consciousness in the same way a physical book does. It can take you down the rabbit hole.

Sounds interesting, and 167 DPI is a very nice screen resolution. But if everything is set in the exact same typeface — if Kindle’s e-books are delivered as strings of text rather than as designed pages — then the Kindle will not replace books. I think PDF is the only feasible e-book format today.